Page:Great Neapolitan Earthquake of 1857.djvu/526

422 portions that had been broken out and disjointed, in the direction of the original wave, and by it, having been thrown afterwards, in directions nearly orthogonal to it.

It was difficult to get any indication, from which to calculate velocity here, or any approximation to the amplitude of the wave, nearly everything being totally prostrate and the history of its fall, a blank; the bells, for example, of the church, were many feet deep under stone and rubbish.

The direction of the wave being generally sub-abnormal, rendered it difficult to find any walls at the Castello, directly across the plane of which, the force had passed, and so circumstanced, that, being found still standing, they would afford to calculation, a limit beyond which, the total velocity of the summit of the hill could not have reached. In fact, had the wave and first oscillation of the hill, together been normal or subnormal to the walls of the Castello, not one stone of it would have been left standing; its remnant owed its remaining erect, mainly to the diagonal direction of its walls in reference to the wave, as may be readily seen, in the case of the buttressed curtain wall to the left in Photog. No. 251.

I was enabled, however, to find one massive piece of wall at the north side, whose condition admitted of its being used as a tolerable measure of this limiting velocity. Its lengthway was 72° E. of north; it was therefore within 12° of being transverse to the path of the primary wave.

It was a curtain wall of old rubble masonry, connected with buildings or towers at both ends about 40 feet apart, but in advance of one, so that it had very slight bond with that tower; while at the other an old settlement, or crack,